The present invention is directed to methods and apparatus for dispensing material, particularly granular chemical material. The invention is particularly adapted for dispensing agricultural material, such as pesticides, herbicides, and fungicides from an apparatus driven over terrain onto which the treatment material is applied.
Agricultural dispensing apparatus, more commonly known as granular or broadcast spreaders, generally include a wheeled vehicle, either self powered (e.g., motorized) or manually driven, including a housing having a hopper for receiving a container holding product to be dispensed, and metering means for controlling the quantity of material flowing from the product container, by gravity feed, on to dispensing means, such as a spinning plate positioned beneath the metering means for receiving material deposited thereon and dispensing material therefrom by rotational forces. The apparatus is driven along the terrain to be treated, and the material to be applied to the terrain is dispensed from the moving apparatus. Known apparatus are exemplifed by the following United States patents: U.S. Pat. Nos. 460,120; 835,040; 873,497; 1,956,560; 2,366,644; 2,489,171; 2,572,060; 2,974,963; 3,082,007; 3,586,246; 3,602,394; 4,032,074; 4,283,014; 4,548,362; 4,597,531; 4,609,153; 4,785,976; 4,867,381; 5,009,344; 5,029,624; 5,060,701; 5,145,116; 5,288,017; 5,294,060; 5,638,988; and 5,641,011.
The disclosure of U.S. Pat. No. 5,029,624, issued on Jul. 9, 1991 and entitled "Closed Granular Chemical Handling System" which discloses a known dispensing system for granular material, is expressly incorporated by reference herein. The disclosure of Australian Patent Application No. 16519/97, published September-October 1997, which discloses a valve system particularly for use with agricultural equipment, is also expressly incorporated by reference herein.
Granular agricultural dispensers generally include metering systems having a rotatable apertured metering disk disposed between a product container and means for discharging product from the dispensing apparatus. Removal of the metering disk from the apparatus is required for several different purposes including inspection, maintenance, repair, and replacement. Moreover, different metering disks can be interchangeably mounted in the dispensing apparatus to adjust the pattern of flow of product through the rotatable metering disk, the quantity of product flowing through the metering disk, or the rate at which product flows through the metering disk. In the known dispensing devices, it is necessary to substantially disassemble the entire apparatus to remove the metering disk from the meter assembly.
It is the primary object of the present invention to provide means for readily removing the metering disk of a dispensing apparatus without disassembling the apparatus. It is a further object of the present invention to provide guide means by which the metering disk can be readily returned to its proper operating position within the dispensing apparatus.
Other objects, improvements and advantages of the present invention will be apparent from the following discussion herein.